Predictive factors for hypothyroidism in childhood autoimmune thyroiditis: insights from long-term follow-up

Laura Astara; Laura Pinna; Giulia Faa; Alessandro Colleo; Francesco David; Sandro Loche; Angelico Lampis; Stefano Mariotti; Francesco Boi; Giulia Lanzolla

doi:10.1530/endoabs.110.P1222

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Endocrine Abstracts (2025) 110 P1222 | DOI: 10.1530/endoabs.110.P1222

ECEESPE2025 Poster Presentations Thyroid (141 abstracts)

Predictive factors for hypothyroidism in childhood autoimmune thyroiditis: insights from long-term follow-up

Laura Astara ¹ , Laura Pinna ¹ , Giulia Faa ¹ , Alessandro Colleo ¹ , Francesco David ¹ , Sandro Loche ¹ , Angelico Lampis ¹ , Stefano Mariotti ¹ , Francesco Boi ¹ & Giulia Lanzolla ¹

Author affiliations

¹University of Cagliari, Cagliari, Italy

JOINT2904

Introduction: Predictive factors for hypothyroidism progression in children with autoimmune thyroiditis (AIT) remain unclear.

Objectives: To characterize the clinical presentation of AIT, assess long-term outcomes, and identify predictive factors for disease progression.

Methods: Data from 127 consecutive patients under 18 years of age at presentation were analyzed (mean follow-up:7.1 years; range:0–20yr).

Results: At presentation, 57% of patients were euthyroid, 28% had subclinical hypothyroidism, and 15% had overt hypothyroidism. By the end of follow-up, among euthyroid children, 20.5% developed overt hypothyroidism, and 6.8% progressed to subclinical hypothyroidism. The subclinical hypothyroidism group showed dynamic changes: 45.7% of patients progressed to overt hypothyroidism, while 37.1% reverted to euthyroidism. Finally, the overt hypothyroidism group did not show significant changes. Patients progressing to hypothyroidism were younger at diagnosis (P = 0.0008) with higher thyroid peroxidase antibodies (AbTPO) titers (P < 0.0001), higher TSH (P < 0.0001) and lower FT4 levels (P = 0.0026). Thyroid volume >6mL increased hypothyroidism risk (P = 0.0060, OR:0.347,95%CI:0.15-0.75). Multivariate analysis confirmed that AbTPO titers influence TSH levels at follow-up (P < 0.0001). Cutoff thresholds were established to refine predictive accuracy. Patients diagnosed under 10 years of age (P = 0.043, OR:0.458,95%CI:0.22-0.96), with AbTPO>92 IU/mL (P < 0.0001, OR:25,95%CI:8.78-63.11), and TSH>4.95 μIU/mL (P < 0.0001, OR:15.43,95%CI:5.61-37.57) had highest risk of developing hypothyroidism. Notably, AbTPO>92 IU/mL and TSH>4.95 μIU/mL demonstrated the strongest predictive power. AbTPO titers had a positive predictive value (PPV) and negative predictive value (NPV) of 83%, while TSH >4.95 yielded a PPV of 79% and an NPV of 80%.

Conclusions: Twenty percent of euthyroid children developed hypothyroidism, compared to 45.7% of those with subclinical hypothyroidism. TSH>4.95 μIU/mL and AbTPO titers had the greatest predictive power. Patients diagnosed under 10 years of age had a higher risk of developing hypothyroidism, suggesting that prolonged exposure to autoimmunity may play a role. Further studies are needed to validate predictive models for hypothyroidism development in children with AIT.